import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

/**
 * @Author liangzai
 * @Description:
 */
public class UdpEchoServer {
    private DatagramSocket socket = null;

    public UdpEchoServer(int port) throws SocketException {
        socket = new DatagramSocket(port);
    }

    private void start() throws IOException {
        System.out.println("服务器启动!");
        while (true) {
            DatagramPacket requestPacket = new DatagramPacket(new byte[4090],4090);

            socket.receive(requestPacket);

            String request = new String(requestPacket.getData(),0,requestPacket.getLength());

            String response = process(request);

            DatagramPacket responsePacket = new DatagramPacket(response.getBytes(),response.getBytes().length,
                    requestPacket.getSocketAddress());

            socket.send(responsePacket);
            //打印日志
            System.out.printf("[%s : %d] req : %s, resp : %s",requestPacket.getAddress(),requestPacket.getPort()
            ,request,response);
        }
    }

    private String process(String request){
        return request;
    }

    public static void main(String[] args) throws IOException {
        UdpEchoServer server = new UdpEchoServer(9090);
        server.start();
    }
}
